This invention relates generally to products having rigid or semirigid portions where it is an advantage to have such members foldable or flexible relative to each other. Examples of applications which might encompass such products include large mats which are advantageously folded for storage and/or for shipping. These mats include floor coverings and mats as might be used for chair mats or animal cage mats. Other applications include book hinges, window blinds, doors, housings, and generally any large flat rigid or semirigid object which could advantageously be flexed or folded, such as for shipping, storage, or in applications where living hinges are of use. In addition, flexible joints for rigid items such as conduit and pipe may be advantageous.
U.S. Pat. No. 4,476,174 to Carrera relates to a composite plastic chair mat having a flexible strip laminated into the underside of the mat, i.e., the floor engaging surface, and a transverse slit which overlays the flexible strip to allow the mat to be folded.
U.S. Pat. No. 4,448,625 to Carrera is a division of the above-cited reference and relates to the process by which the chair mat is made. The construction of this mat presents several disadvantages. The slit provides a gathering spot for dirt and a potential failure of the mat, especially under the long term application of pressure from office furniture. The slit could further be a safety hazard both at the slit face and at the mat edges where the user could trip over any unevenness which could arise. Moreover, the wear at the slit could present a poor appearance.
U.S. Pat. No. 4,387,128 to Emms et al also relates to a hinged foldable structure having a flexible hinge means.